That's was interesting - 117k lbs to LEO is quite a big chunk of mass. Launch end of next year - so a while to wait!

Although Elon Musk really does need to practice his public speaking a bit more!!!

According to the SpaceX website: “Falcon Heavy will arrive at our Vandenberg, California, launch complex by the end of next year, with liftoff to follow soon thereafter. First launch from our Cape Canaveral launch complex is planned for late 2013 or 2014.”

Press got it wrong as usual, but do concede interpretation of 'liftoff to follow soon thereafter' does leave a bit of uncertainty. However SpaceX timeframes are around x1.2 so I'll go for late 2013 rather than late 2012

Well, maybe they didn't believe Elon . I'm not sure where he got the 95klbs thrust figure. According to this the Falcon 1A had 75klbs and 1B 85klbs. Marcus says 125klbs for the 1C, and 1D will then be 140klbs. Maybe he just misspoke, and meant 75klbs?

Anyway, that is quite an impressive ramp-up. Could it be that they were running the 1A way below the original design specs, and that much of this upgrading is really just expanding the envelope, as they gain more test data and confidence in their design and manufacturing processes?

_________________Say, can you feel the thunder in the air? Just like the moment ’fore it hits – then it’s everywhereWhat is this spell we’re under, do you care? The might to rise above it is now within your sphereMachinae Supremacy – Sid Icarus

Could it be that they were running the 1A way below the original design specs, and that much of this upgrading is really just expanding the envelope, as they gain more test data and confidence in their design and manufacturing processes?

Could be. Or they just learn that they can actually safely go above original specs. Just like SSME that routinely run at 109% of original specs

Wikipedia wrote:

Specifying power levels over 100% may seem nonsensical, but there is a logic behind it. The 100% level does not mean the maximum physical power level attainable. Rather it is a specification, decided on early during SSME development, for the expected rated power level. Later studies indicated the engine could operate safely at levels above 100%, which is now the norm.

Could it be that they were running the 1A way below the original design specs, and that much of this upgrading is really just expanding the envelope, as they gain more test data and confidence in their design and manufacturing processes?

Could be. Or they just learn that they can actually safely go above original specs. Just like SSME that routinely run at 104.5% of original specs

Wikipedia wrote:

Specifying power levels over 100% may seem nonsensical, but there is a logic behind it. The 100% level does not mean the maximum physical power level attainable. Rather it is a specification, decided on early during SSME development, for the expected rated power level. Later studies indicated the engine could operate safely at levels above 100%, which is now the norm.

Well, maybe they didn't believe Elon . I'm not sure where he got the 95klbs thrust figure. According to this the Falcon 1A had 75klbs and 1B 85klbs. Marcus says 125klbs for the 1C, and 1D will then be 140klbs. Maybe he just misspoke, and meant 75klbs?

As configured for use on Falcon 1 vehicles, the Merlin 1C had a sea level thrust of 350 kN (78,000 lbf), a vacuum thrust of 400 kN (90,000 lbf) and a vacuum specific impulse of 304 seconds. In this configuration the engine consumed 140 kg (300 lb) of propellant per second. Tests have been conducted with a single Merlin 1C engine successfully running a total of 27 minutes (counting together the duration of the various tests), which equals ten complete Falcon 1 flights.[15]

As configured for use on the newer Falcon 1e and Falcon 9 vehicles, the Merlin 1C has a sea level thrust of 560 kN (125,000 lbf), and an isp of 300.[16]

I assume they first made the 1C work with the necessary thrust to get Falcon 1 off the ground (78-ish klbf), then gradually improved it. So at some point it was probably 95 klbf, then with further tweaking they finally arrived at 125 klbf.

But according to the same Wikipedia article they actually did upgrade parts of the engine between versions, so it wasn't just pushing the envelope. Still, the 1A version probably had quite a bit of margin left, otherwise they wouldn't have been able to get it up to almost twice its original performance.

_________________Say, can you feel the thunder in the air? Just like the moment ’fore it hits – then it’s everywhereWhat is this spell we’re under, do you care? The might to rise above it is now within your sphereMachinae Supremacy – Sid Icarus